Technical Field of the Invention
This invention relates generally to communication networks and in particular to carrying different types of traffic over the same medium.
Description of Related Art
Mutually asynchronous traffic deriving its timing from two or more sources is traditionally transported over separate transport media to ensure proper timing is maintained at the receiving network device. However, providing separate transport media increases the cost and requires separate interfaces to be installed at both the transmitting network device and the receiving network device.
For example, Ethernet traffic and non-Ethernet traffic deriving their timing from different sources are currently transported over different media. If the Ethernet traffic and non-Ethernet traffic could be transported over the same media, the number of optical fibers that need to be deployed in the network could be reduced, thereby resulting in significant savings to the customer.
However, providing clock traceability for traffic deriving its timing from multiple sources has proven difficult. For example, Common Public Radio Interface (CPRI) links typically transport CPRI traffic between the radio equipment control (REC) and radio equipment (RE) of wireless basestations. Carrying Synchronous Ethernet traffic on the same medium as the CPRI traffic necessitates maintaining the stringent timing requirements of both.
In order to retain clock traceability for both Ethernet traffic and non-Ethernet traffic over a medium deriving its timing from the timing source of the non-Ethernet traffic (e.g., CPRI traffic), the receiving network device must to be able to reconstruct the Ethernet clock of the transmitting network device. However, no mechanism currently exists to enable reconstruction of the Ethernet clock at the receiving network device.